The present invention relates to devices for securing sliding doors and the like in a fully closed or partially opened, vented position.
One simple and common type of device for locking sliding doors comprises a relatively long and narrow bar of metal, wood or plastic loosely disposed in the bottom channel of the sliding door frame, between the sliding door and a vertical frame member at the back of the door, so as to block the sliding movement of the door. The length of the bar is usually selected either to secure the door in a fully locked position, or to permit venting by allowing the door to be opened slightly before it encounters and is stopped by the bar. Some devices of this type have extensions which allow them to secure a door in either a fully closed or partially open, vented position.
However, devices of the type described above are not without their problems. For example, these devices are designed to stop the door by a bracing force applied against the bottom of the door. As a result, the door can sometimes be jarred and lifted over the device. Moreover, since such devices are not normally attached to either the door or the frame, they can sometimes be easily dislodged from the bottom channel of the door frame in which they rest, particularly when the door is opened for venting purposes.
In an attempt to solve some of these problems, special devices for securing sliding doors have been designed specifically for this purpose. Such devices generally comprise elongated bars having one end hingedly attached to a vertical member of the door frame, above the bottom frame channel, at a point approximately half way up that member. To secure the door, the bar is pivoted to a horizontal position so that the free, unhinged end of the bar is in abutting contact with the sliding door. To unsecure the door, the bar is pivoted out of the way into a vertical position in which it is aligned with and substantially against the vertical door frame member. Some pivoting bars have a main portion sized to secure the door in a partially opened position for venting purposes, with an extension which when deployed allows the extended bar to secure the sliding door in a fully closed position.
While the pivoting bars described above normally have one end hingedly attached to a vertical member of the door frame, the free end in some instances is held against the sliding door solely by friction, or supported (but not secured) by a U-shaped cradle. Both of these arrangements are unsatisfactory because they tend to permit the free end of the bar to slip, be dislodged or lifted out of its cradle. Even the few commercially available security devices of this type, with provisions for locking the free end of the bar to the sliding door, tend to be costly, difficult to install and inconvenient to use, as they usually require a key.
The security problems that arise from the above situation are particularly acute when the door is partially opened for venting purposes. Although the vent opening is typically too narrow for even a small child to pass through, it is usually sufficiently wide for someone to introduce a pole or other elongated implement for the purpose of dislodging the bar from either the bottom of the sliding door channel or from the cradle supporting the free end of the bar. Therefore, a significant disadvantage of existing bar-type devices for securing sliding doors and the like is that they are either fairly easily overridden and dislodged, or they are too elaborate, costly, and inconvenient to use.
Another significant security problem exists when the sliding door slides on the outside with respect to the door frame. While the devices described above have some utility on sliding doors that slide inside with respect to the door frame, they generally do not work well or at all on outside sliding doors.
From the foregoing, it should be apparent that a need exists for a simple, inexpensive device which is easy to install and use, for securing sliding doors and the like, whether or not they slide on the inside or the outside, and which will keep the bar in place when the sliding door is either fully locked or partially opened for venting purposes. The present invention satisfies this need and provides further related advantages.